Aim: To determine the prevalence of vitamin D hypovitaminosis among obese and overweight schoolchildren.
Design: A cross-sectional population based sample.
Methods: In a cross-sectional study, 301 students (177 girls and 124 boys) aged 11-19 years were selected by multistage stratified sampling design. Subjects were classified according to their body mass index as obese, overweight and normal. Serum 25-hydroxyvitamin D (25-OHD), intact parathyroid hormone (iPTH) and alkaline phosphatase (ALP) were measured in late winter months. Vitamin D deficiency was defined as a 25-OHD 20 ng/ml.
Results: The prevalence of hypovitaminosis D was found as 65% in all students. Vitamin D deficiency was found in 12% and insufficiency in 53% of all students. Vitamin D deficiency in female students was about two times more common than in males. In obese and overweight schoolchildren with hypovitaminosis D, serum 25-OHD levels decreased as BMI increased. There were no correlations between serum 25-OHD and ALP and iPTH levels.
Conclusion: Vitamin D deficiency and insufficiency are common in obese and overweight schoolchildren, especially in girls. Obesity could be a risk factor in terms of hypovitaminosis D in adolescents. Vitamin D supplementation should be administered particularly to adolescent girls.
Keywords: Vitamin D; adolescents; hypovitaminosis D; obesity; schoolchildren.